Draft system for flying-boats.



G. H. CURTISS.

DRAFT SYSTEM Toa FLYING BOATS.

APPLICATION FILED NOV. I8. ISIG.

Patented Nov. 6, 1917.

2 SHETS-SHEET I- l" GLENNHCUm-ls.

G. H. CURTISS.

. DRAFT SYSTEM FOR FLYING BOATS.

APPLICATION FILED Nov.1a. Isle.

Patented Nov. 6, 191.7.

2 SHEETS-SHEET 2.

wvewtoz GLENN H .Cum-Iss.

UNITED sTATEs PATENT oEEToE.

GLENN H. CURTISS, 0F BUFFALO, NEW YORK, ASSIGNOR TO CURTISS AEROPLANE AND MOTOR CORPORATION, A CORPORATION OF NEW YORK.

DRAFT SYSTEM FOR FLYING-BOATS.

Specification of Letters Patent.

Patented Nov. 6, 1917.

Application led November 18, 1916. Serial No. 132,106.

To all whom it may concern:

Be it known that I, GLENN I-I. CURTISS, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented certain new and useful Improvements in Draft Systems for Flying-Boats, of which the following is a specification.

This invention relates to heavier-than-air iying machines and more particularly relates to an improved draft system for multimotored hydroaeroplanes and flying boats.

In the larger high powered types of aircraft, where the thrust value is enormous, it is customary to locate the several motor units of a multiple unit power plant intermediate the supporting surfaces or planes, each motor unit having an individual mounting which, in a Curtiss type of flying boat, may be generally described as comprising front and rear wing post frames and engine bed beams intermediately interconnectingl them. By this arrangement the center of thrust is removed from the plane of the center of resistance for location considerably above the hull or body of the craft. Bearing in mind the relation and location of these two theoretical 'centers and the enormity of thrust value occasioned by the simultaneous operation of the several power units, it is evident that some means must be provided whereby the full thrust stresses may be directly and eifectually transmitted laterally inwardly to regions of resistance or drift. Hence, it is to this end that the present invention is designed.

Another and important object of the invention resides in the utilization of built-in wing spars in connection with the cross-arranged lift and drift wires for transmitting the thrust stresses interiorly of the hull.

In describing my invention in detail, reference will be had to the accompanying drawings wherein like characters of reference designate like or corresponding parts throughout the several views, ofwhich:

Figure 1 is a front elevation of the engine section of a flying boat illustrating diagrammatically the arrangement of cables and struts utilized in the transmission of thrust stresses directed tothe interior of the hull;

Fig. 2 similarly illustrates the arrangement referred to in side elevation;

Fig. 3 is a perspective view illustrating by shaded lines the relative arrangement of the draft system units, and

Fig. 1 is a detail perspective View.

Before undertaking a general description of the system of my invention, it is to be thoroughly'appreciated that it is not my intention to limit the application of the invention to multimotored flying boats although craft of this type had been and are being deyeloped (almost exclusively) along larger mes.

The hull or body of the craft, indicated by dotted lines in Figs. 1 and 2 and designated in its entirety by the numeral 10, may be generally described as comprising a fore body 11, an extended tail 12, and fin excrescencies 13, the latter augmenting laterally the hydroplaning bottom and extending rearwardlyy from the bow aft to a planing step 14 located in the approximate transverse vertical plane of the center of gravity designated CG.

Built-in wing spars 15 and 16 extend intermedately across the hull, one in advance of and the other aft ofthe vertical plane of the step 14. lThese spars collectively constitute a base for the engine section panel of the lower supporting plane 17.

Front and rear wing Vpost frames designated respectively 18 and 19 interconnect the engine section panel of the lower supporting plane 17 with the engine section panel (not shown) of the upper supporting plane. Wing spars 20 and 21, equal in length to the wing spars 15 and 16, constitute a base for the upper engine section panel to accordingly provide with the lower panel, an engine section biplane cell which in length yis sufficient to extend laterally considerably beyond the sides of the hull.

Center struts, front and rear, designated respectively 22 and 23 interconnect and brace the wing spars of the engine section panels. These struts, together with struts 24 and 25 which extend inwardly diagonally from the front and rear wing post frames downwardly in converging relation to the spars 15 and 16 respectively at the foot of each center strut 22 and 23, effectually brace the biplane panel cell.

units, of which in the present instance there are two arranged intermediate the supporting surfaces of the machine. lrlhe downwardly converging braces 24 and 25 engage at the terminals of the engine beds to transmit all lateral stresses to the beams l5 and 16 at the foot of the center struts 22 and 23. Lift and drift wires 27, cross arranged, tie up the cell to constitute it a rigid unified whole. rlhe moto-r units ll have designated 28 and 29.

rl`he foregoing construction and arrangement of parts, although admittedly preferred, forms no part of the invention disclosed except insofar as it functions in combination with the draft system hereinafter disclosed. Having in mind the relation and location of the theoretical center of thrust and the theoretical center of resistance designated on the drawing as C. T. and C. R., respectively (referred to hereinbefore), together with the enormity of thrust value occasioned by the simultaneous operation of the two power units, it is evident that a means must be provided to transmit the total thrust stress from the power units to the interior of the hull. With this in view, cables 30, two in number, interconnect theD opposed motor beds at their forward ends with the rear center strut 23 in a horizontal plane and at a point directly inline with the rear upper terminal of a forwardly and downwardly extending diagonal brace 3l. This brace 3l lies in the vertical plane of the fore and aft axis of the machine to engage at its lower forward end with the wing1 spar 15 at the foot of the center strut 22 and in alinement with an interior brace 32 arranged to abut respectively the said spar l5 and a compression block 33 located interiorly of the hull at the center thereof for contact with the interior surface of the hydroplaning bottom. The brace 31 may be describedas an exterior continuation of the brace 32. By the arrangement described, the total thrust value is directly transmitted to a point of maximum resistance, namely, the hydroplaning bottom of the hull. lln flight and in landing, the cables 30 are under tension; the braces 31 and 32 under compression; and the total number of exposed braces minimized.

Certain of the cross-arranged lift and drift wires 27 in connection with the stub wing structures supplement the stress transmission laterally inwardly from the motor units to the compression brace 32.

'lo compensate for drift strains incident to Hight, cables 34 extend from the rear upper wing spar 21 at points of intersection with the wing post frames 19 forwardly and downwardly to the engine beds 26 to points where the cables 30 are fastened and the lateral braces 24C engage. Drift strains are in this way also transmitted, via the cables 30 and the compression member 3l-32, di-

rectly to the hydroplaning bottom of the hull.

For obvious reasons it is impractical in a multi-metered machine to provide a plural number of compression members, one for each motor unit. To do so would add enormously to the head resistance without a proportionate gain in strength. By the draft system which have evolved,l the total thrust and landing stresses are directly carried to the interior of the hull and there uniformly distributed by the utilization of a single compression member, 31-32 in conjunction with cables 30 which directly connect the outer rear end of the compression o member to the forward end of the engine beds or spars.

Although l have described more or less precise forms and details of construction, lt do not intend to be understood as limiting myself thereto as l contemplate changes in form, the proportion of parts and the substitution of equivalents as circumstances may suggest or render expedient and without departing from the spirit of the invention as claimed.

ldhat is claimed is:

l. lrn an aircraft, the combination with supporting surfaces, a body, and av multiple unit power plant, of a compression member arranged to transmit thrust stress forwardly into said body, and a draft system arranged intermediate the motor units for .CQnnection with said member.

o2. ln an aircraft, the combination with supporting surfaces, a body, and a multiple unit power plant, of a diagonally downwardly and forwardly inclined compression member arranged to transmit thrust stress forwardly into said body, and a draft system arranged in a horizontal plane intermediate the motor units for connection with said member.

3. ln an aircraft, the combination with supporting surfaces, a body, and a multiple unit power plant, of a compression member extended at one end into the interior of said body, and a draft system including tension cables arranged for connection respectively with the several motor units and said member.

4f. lin an aircraft, the combination with supporting surfaces, a body, and a multiple unit power plant including motor units arranged symmetrically at opposite sides of the longitudinal axis of the craft, of a draft system comprising tension cables arranged for connection at one end to the respective motor units and for intersection at their opposite ends at a point in the vertical plane of said axis, and a compression member arranged for contact at said point of intersection to transmit thrust stresses forwardly into said body.

5. lln an aircraft, the combination with supporting surfaces, a body, and a multi le unit power plant, of a compression mem er arranged to extend into said body from without at a point intermediate the leadingv and trailing edges of said supporting surfaces, and a draft system including cables commonly connected to said member at the point aforementioned and separately connected to the several motor units.

6. In an aircraft, the combination with supporting surfaces, a body, and a multiple unit power plant, of a compression member arranged to extend diagonally downwardly and forwardly from a lpoint without and i11- termediate the supporting surfaces to a point within said body, and a draft system including tension cables arranged to extend forwardly from a common point of connection with said compression member to the se arate motor units.

In an aircraft, the combination with supporting surfaces, a body, and a multiple unit power plant arranged to locate the center of thrust in a plane out of alinement with the plane of the center of resistance, of a compression member arranged to extend from a point in the horizontal plane of the theoretical center thrust forwardly into said body, and a draft system arranged to interconnect said member and the several motor units.

8. In an aircraft, the combination with supporting surfaces, a body, and a multiple v unit power plant arranged to locate the center of thrust in a plane vout of alinement with the plane of the center of resistance, of a compression member arranged to extend diagonally downwardly and forwardly from a point in the horizontal plane of the theoretical center of thrust into said body, and a draft system including cables commonly connected to said member and separately con- 4nected to the several motor units.

9. In an aircraft, the combination with supporting surfaces, a body, and a multiple unit power plant arranged to locate the center of thrust in a plane out of alinement with the plane of the center of resistance, of a compression member arranged to extend into the interior of the hull from a point without and intermediate the supporting surfaces, and a draft system arranged in the horizontal plane of said center of thrust to interconnect the compression member and several motor units.

10. In an aircraft, the combination with supporting surfaces, a body, and a multiple unit power plant arranged to locate the cen'- ter of thrust in a plane out of alinement theoretical center of thrust forwardly to a point of maximum resistance interiorly of said body, and a draft system including tension cables commonly connected to said member at its aft extended terminal and separately connecting the several motor units forwardly of its point of connection with said member.

11. In an aircraft, the combination with supporting surfaces, a body, and amultiple unit powerI plant arranged to locate the center of thrust in a plane out of alinement with the plane ofthe center of resistance, of a compression member arranged to extend forwardly into the interior of said body from a point in the horizontal plane of said center of thrust, tension means connecting the extended aft terminal of said compression member with the separate motor units, a tension means for transmittin the drift stresses directed to the interior o said body via the tension means and compression member aforesaid.

12. In an aircraft, the combination with supporting surfaces, a body, and a multiple unit power plant arranged to locate the center-of thrust in a plane out of alinement with the plane of the center of resistance, av tension means for transmitting the drift stresses to the motor unit supports direct, a compression member arranged to extend into the interior of said bodyv for contact at a point of maximum resistance, and tension means for transmitting said stresses commonly to said compression member from the respective motor unit sup orts.

13. In an aircraft, the com ination with supporting surfaces, a body, and a multiple unit power plant, of a draft system including tension devices arranged for rearward extenslon from the respective motor umts and a thrust transmitting means arranged to continue the transmission of thrust stresses into the interior of said body.

' 14. In an aircraft, the combination with supporting surfaces, a body, and a multiple unit power plant, of a draft system includ. ing tension cables arranged to extend rearwardly from the respective motor units, and a means for continuing the transmission of thrust stresses into the interior of said body via the supporting surfaces.

15. In an aircraft, the combination with supporting surfaces, a body, and almultiple unit power plant, of a draft system including a compression member arranged to extend interiorly of said body, and a means arranged to transmit thrust stresses by in dependent paths commonly to saidmember.

In testimony whereof I affix my signature.

GLENN H. CURTISS.

Copies of thin patent may be obtained for ve cents each. by addressing the Commissioner of Patente. Washington, D. 0. 

